The invention relates to a device for protecting medical apparatus, in particular from contamination by infectious agents.
Specifically, though not exclusively, the invention can be usefully applied to an apparatus for extracorporeal blood treatment, in particular for treatment of renal insufficiency.
In particular, the invention relates to a transduction-protection device comprising a containing hollow body, having an inlet for communication with an extracorporeal circuit, and an outlet for communication with an operator unit of the medical apparatus, for example with a device for measuring the pressure in the extracorporeal circuit. The device of the operation functions as a transducer, which is both able to transmit pressure from the inlet to the outlet allowing for no drop in pressure and also as an aseptic barrier which protects the medical apparatus from infectious agents originating from the patient.
In more detail, the present invention relates to a device comprising a containing hollow body having an inlet comprising a first tubular connector, destined to be connected to a fluid line associated during operation with an extracorporeal fluid transport circuit, and an outlet comprising a second tubular connector, destined for connection with a fluid line associated during operation to an operator unit of a medical apparatus, the operator unit comprising, for example, a pressure gauge; the first and second tubular connectors being in reciprocal gas communication through an internal cavity of the hollow body, which contains a hydrophobic membrane which defines within the cavity an anti-contamination barrier which is gas-permeable and which is arranged transversally between the first and second tubular connectors.
The device enables transmission of the pressure from the extracorporeal fluid transport circuit to the pressure gauge, without significant losses of head, while at the same time protecting the operators, the medical apparatus, which the pressure gauge is part of, and the surrounding environment, from the risk of contamination from pathogens originating from the fluid running in the extracorporeal circuit. The device can further protect the extracorporeal circuit and therefore the patient too, from intrusion of extraneous particles originating from the medical apparatus.
Transduction-protection devices of the above-described type already exist in the prior art, for example in patents U.S. Pat. No. 4,314,480, EP 0 652 018, U.S. Pat. No. 5,500,003, U.S. Pat. No. 6,086,762, U.S. Pat. No. 6,506,237 and EP 1 097 725, and are commonly known as “blood catchers” or “transducer-protectors”.
One of the drawbacks of the known devices is their poor security level: the protective function of the membrane can be lost due to micro-lesions in the membrane itself, or imperfections, even microscopic, in the seal around the perimeter edge of the membrane, which edge is sealed and lies between two plastic elements bearing the two tubular connectors, along an ultrasonic plastic welding zone which, apart from solidly joining the plastic elements and the membrane, also guarantees the seal.
A known solution to this drawback consists in predisposing, along the fluid line, two devices in series, in reciprocal fluid communication. Thanks to this solution, even if one of the two devices were to fail, the protective function should be guaranteed by the other device. This solution, however, leads to increases in costs, due to the need to realize two distinct ultrasonic welding processes, one for each device, and also due to the need subsequently to realize a connection to the fluid line of the two devices.